Arm chair



FIG. 1 is a front perspective view of the arm chair showing my new design;

FIG. 2 is a front elevational view;

FIG. 3 is a right side elevational view;

FIG. 4 is a left side elevational view;

FIG. 5 is a rear elevational view; and

FIG. 6 is a top plan view thereof. 

The ornamental design for an arm chair, as shown and described. 